In stamping and forming machines, a strip of stock is fed between upper and lower tooling modules that perform operations on the strip at progressive stages of the feed cycle. This requires that the strip be accurately positioned at each stage. Pilot holes or notches are usually cut in the strip in the first stage of operation that are then used in subsequent stages to accurately align the strip. Should the strip misfeed and the machine continue to run, severe damage can occur to the tooling in the upper and lower tooling modules and the machine itself may be damaged. Various devices have been developed to detect strips that are misfed, including optical and mechanical. Once a misfeed is detected, a clutch in the drive unit is deactivated and a brake engaged. With relatively slow machines, up to the 1400 strokes per minute range, this procedure is adequate, allowing the machine to come to a complete halt in less than 180 degrees of rotation without substantial risk of damage to the tooling or the machine. In the case of a high speed machine, on the other hand, operating at about 3000 strokes per minute or higher, the machine may not be able to be stopped in time to avoid damage once a misfeed is detected. Other devices that have been developed to cope with this problem mechanically disconnect the feed system so that, as the machine is coasting to a stop, the problem is not further aggravated by the feed system continuing to feed stock into the tooling. However, such feed release systems react too slowly for reliable use with a stamping and forming machine operating at high speed. Since machines with clutch and brake drives are not able to stop within 180 degrees of rotation, it is desirable to at least stop the strip feed. However, feed mechanisms are mechanically coupled to the press drive and cannot be quickly stopped when the press is operating at 3000 or more cycles per minute.
What is needed is a feed mechanism having a release system for use in a high speed stamping and forming machine that, upon detection of a misfeed, will reliably disengage the feed mechanism within one half of a single ram stroke cycle.